West System 205B Fast Epoxy Hardener (27.5 fl oz) with Epoxy Metering Pump Set (3-Pack)
Product highlights:
- Medium-viscosity epoxy curing agent
- Used in a majority of bonding situations
- Used at lower temperatures
- Produces a rapid cure that develops quickly
- Mix with 105 Resin in a 5:1 resin to hardener ratio
- 5:1 mixture yields rigid, strong, moisture-resistant solid
- 5:1 mixture has excellent bonding and coating properties
- Not intended for clear coating
In the box
West System 205B Fast Epoxy Hardener (27.5 fl oz)
West System 300 Mini Pumps Epoxy Metering Pump Set (3-Pack)
- West System 300 Mini Pumps Epoxy Metering Pump Set (3-Pack)
- 105 Epoxy Resin Pump
- 205/206 Epoxy Hardener Pump
- 207/209 Epoxy Hardener Pump
- 3 x Extension Tubes for Group Size A Containers
West System 205B Fast Epoxy Hardener (27.5 fl oz)
The West System 205 Fast Hardener is a medium-viscosity epoxy curing agent. It is useful in a majority of bonding situations, and at lower temperatures. This hardener produces a rapid epoxy cure that develops physical properties quickly at room temperature. Mix it with West System 105 Resin (sold separately) in a five-part resin to one-part hardener ratio. The resulting cured epoxy is a rigid, high-strength, moisture-resistant solid. The combination of 105 Resin/205 Fast Hardener has excellent bonding and coating properties. The West System 205 Fast Hardener is formulated to cure well at temperatures as low as 40-degree-F (4-degree-C). There are several things you can do to ensure a full cure when using epoxy in low temperatures.
Pre-Warm the Resin and Hardener
Cold temperatures increase an epoxy’s viscosity, making it harder to dispense, mix and apply. Warming resin and hardener reduces their viscosity, so they flow easily through their dispensing pumps. To pre-warm, place the resin and hardener containers under a warming lamp or in a warm-water bath. Pre-warmed resins and hardeners will not cling as much to your mixing equipment. They’ll also blend more easily, ensuring thorough mixing. A warmer, lower-viscosity mixture flows smoothly during application and readily penetrates porous surfaces.
Dispensing and Mixing Epoxy in Cold Temperatures
Always dispense 105 Resin (sold separately) and 205 Fast Hardener at the proper mixing ratio. Never alter the amount of hardener because this can seriously compromise the epoxy’s ultimate strength. Optional West System 300 Mini Pumps come ready to dispense the correct ratio of resin and hardener. One full pump-stroke of resin for every one full pump stroke of hardener is all you need to remember.
Preparing Surfaces
Between applying coats of epoxy, prepare the cured epoxy surfaces. When coating at cold temperatures, the slower cure can result in a waxy/greasy film on the surface of the cured epoxy, called amine blush. Remove this byproduct of the curing process before you apply the next coat of epoxy. Amine blush is easy to wash away with plain water and a 3M Scotchbrite pad. Don’t let the water evaporate. Dry the surface with plain white paper towels. Don’t use rags, because they can contaminate the surface with laundry softeners and anti-cling ingredients.
Allow the Epoxy Extra Time to Cure
Allow the epoxy additional time to cure before you remove clamps or stress the joints. As a general rule, double the cure time for every 18-degree-F (10-degree-C) drop in temperature. Allow even more cure time when for bonding pre-stressed joints, bent laminations, or joints that will undergo high loads. Elevate the temperature of the partially cured epoxy. This can help the resin and hardener complete their cross-linking. It’s a good way to boost the epoxy’s physical properties, even after a week at cold temperatures.
West System 300 Mini Pumps Epoxy Metering Pump Set (3-Pack)
These 300 Mini Pumps from West System are designed for convenient and accurate metering of Group A, B, and C resin-based epoxy. This 300 Mini Pump Set contains one 105 Epoxy Resin Pump, one 205/206 Epoxy Hardener Pump, and one 207/209 Epoxy Hardener Pump. Pumps mount directly on the resin and hardener containers and eliminate the mess involved with measuring by weight or volume.
Calibrated for Precision
These pumps are calibrated to deliver the proper working ratio with one full pump stroke of resin for each one full pump stroke of hardener. 105/205-206 pumps deliver approximate 0.8 fl oz of resin/hardener with one full stroke of each pump. 105/207-209 pumps deliver approximately 0.9 fl oz of resin/hardener with one full stroke of each pump.
For Group A, B, and C Containers
Made of durable polypropylene, the Mini Pumps gives years of dependable service. As packaged, the pumps are ready to install on the Group Size B containers. A package of extension tubes for Group Size A containers is included with this pump set. Group Size C extension tubes are included with the 105-C Resin and 207-SC or 209-SC Hardener containers.
Accurate Metering
West System Epoxy Metering Pumps are calibrated for accurate metering of West System Epoxy Resin and Hardener at the proper mix ratio, while eliminating mess and guesswork. The correct epoxy resin to hardener ratio is important to ensure that the epoxy reaches its full potential for cured physical properties.
Ratio Verification
The ratio of each pair of Mini Pumps is controlled by the installation of a clip, that limits the stroke (and volume) of one or both of the pumps. All Mini Pumps are carefully inspected during this operation and during packaging. But the final test of a pump’s performance can’t be made until it is actually pumping resin or hardener. The ratio verification test described in the instructions confirms that both pumps are dispensing the correct volume and that the ratio of resin to hardener is within a critical narrow range.
Why Use Epoxy Metering Pumps?
Epoxy metering pumps ensure you’re using the correct ratio of resin to hardener, crucial to epoxy performance. Depending on the hardener you select, West System Epoxy is mixed at a ratio of five parts resin to one part hardener, or three parts resin to one part hardener. At the proper mix ratio, the number of chemically reactive sites in the resin balances the number of reactive sites in the hardener. The resin molecules are larger than the hardener molecules, and have few reactive sites, hence the 5:1 or 3:1 ratio. When the mix is stirred thoroughly, the resin and hardener molecules react to develop full strength.
Epoxy Metering Pumps for Fast Dispensing
West System Pumps dispense epoxy faster than any pump they’ve ever offered. These pumps work by trapping a fixed amount of resin and hardener then forcing (displacing) that trapped volume into the discharge tube. These offers improved epoxy pumping performance because changes in viscosity due to temperature change do not affect their performance.